1. Field of Invention
The invention relates to lighting devices for Christmas and more particularly to a Christmas light string having a socket for electrically connecting to another Christmas light string so that a number of Christmas light strings can be assembled together to form a lighting unit having an increased length.
2. Description of Related Art
There have been numerous suggestions in prior patents for Christmas light string. For example, U.S. Pat. No. 6,344,716 describes a Christmas light string having a plurality of parallel group devices to assure that voltage drop across each five-lamp group is always approximately three volts regardless of the number of bulbs missing, burned out, or whose contacts are degraded.
Further, decorating a Christmas tree with one or more Christmas light strings is well known. Typically, a Christmas light string comprises a plug, an adapter, a plurality of lamps, and a cord connecting them together. In use, the plug is inserted into a wall outlet for electrically connecting to 110 AC volts or 220 AC volts power. The AC power is rectified by the adapter to convert into DC having a voltage of, for example, 24 volts. And in turn, the lamps are powered by 24 DC volts.
However, whether electrically connected in series or parallel, the number of lamps, mounted on a Christmas light string is limited due to the low voltage DC source. And in turn, it limits the length of the Christmas light string. It is often that a person has to prepare a number of Christmas light strings and connect each of them to an independent power source (e.g., a wall outlet or a power strip) in order to increase length if such need arises. However, this not only increases the cost due to, for example, the buying of power strips but also is not practical if there is only one wall outlet available. Thus, the need for improvement still exists.